US5220314A - Liquid crystal display apparatus and method of performing liquid crystal display - Google Patents
Liquid crystal display apparatus and method of performing liquid crystal display Download PDFInfo
- Publication number
- US5220314A US5220314A US07/532,811 US53281190A US5220314A US 5220314 A US5220314 A US 5220314A US 53281190 A US53281190 A US 53281190A US 5220314 A US5220314 A US 5220314A
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- US
- United States
- Prior art keywords
- display
- liquid crystal
- display information
- data
- crystal display
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/04—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions
- G09G3/16—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions by control of light from an independent source
- G09G3/18—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions by control of light from an independent source using liquid crystals
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/12—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays
- H04N3/127—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by switched stationary formation of lamps, photocells or light relays using liquid crystals
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2044—Display of intermediate tones using dithering
- G09G3/2051—Display of intermediate tones using dithering with use of a spatial dither pattern
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2044—Display of intermediate tones using dithering
- G09G3/2051—Display of intermediate tones using dithering with use of a spatial dither pattern
- G09G3/2055—Display of intermediate tones using dithering with use of a spatial dither pattern the pattern being varied in time
Definitions
- This invention relates to a liquid crystal display apparatus in which color display information is converted into information about luminance of liquid crystal display used for driving a liquid crystal so as to provide a liquid crystal display and a method of performing a liquid crystal display, and more particularly to this type of liquid crystal display apparatus and method capable of alleviating flicker in picture and display flow which occur when display data of a display form pursuant to the dither method is displayed in accordance with gradation display of luminance.
- the dither method referred to herein signifies a technique of realizing binary display of graded images of various half tones by making use of human visual characteristics, as well known in the art.
- a frame base thin-out method has been proposed to achieve gradation display. That is, a liquid crystal is driven in accordance with an effective value of voltage applied to one dot and luminance of display is proportional to the effective value.
- the frame base thin-out method within a predetermined number of frames, some frames are turned on while the remaining frames are turned off and the rate at which the frames are turned on and turned off is call a thin-out rate and the rate is repeated to control the effective value of the applied voltage to the liquid crystal display, thereby performing, for example, half tone display of luminance in proportion to the effective value.
- the frame base thin-out method has a disadvantage that a flicker occurs in the image display each time a "turn on” operation is switched to a "turn off” operation and vice versa. Also, when dots are thinned out at the same timing over the entire screen, a flicker in the image display occurs to degrade the display quality of the image. Therefore, to eliminate the problem of flicker, the dot base thin-out method has been proposed.
- FIG. 4 illustrates a fundamental dot set in the dot base
- FIGS. 5A to 5E show thin-out operation effected at a period of four frames.
- a fundamental dot set 18 of 4 dots consisting of 2 dots in X direction (one odd dot and one even dot) and 2 dots in Y direction (one odd dot and one even dot) on the screen of a liquid crystal panel 17.
- dots are thinned out at different timings for two groups of which one has two staggered dots represented by ⁇ and the other has two staggered dots represented by ⁇ . This thin-out operation will be described specifically with reference to FIGS. 5A to 5E. In these Figures, turned-on dots are depicted by hatched dots.
- FIG. 5B shows a display mode at a thin-out rate of 1/4 in which any one of the four dots constituting the fundamental dot set is turned on once over 4 frames.
- dots ⁇ 1 the dots ⁇ particularly indicated for a first frame
- dots ⁇ 2 to ⁇ 4 are turned off within the remaining frames.
- dots ⁇ 3 the dots ⁇ particularly indicated for a third frame
- the dots ⁇ 1, ⁇ 2, ⁇ 4 are turned off within the remaining frames.
- FIGS. 5C and 5D illustrates similar thin-out modes.
- the dots ⁇ 1 within the first frame and the dots ⁇ 2 within the second frame are turned on with the dots ⁇ 3 and ⁇ 4 within the remaining frames turned off
- the dots ⁇ 3 within the third frame and the dots ⁇ 4 within the fourth frame are turned on with the dots ⁇ 1 and ⁇ 2 within the remaining frames turned off.
- FIG. 5D at the first timing for the dots ⁇ , the dots ⁇ 1 within the first frame, the dots ⁇ 2 within the second frame and the dots ⁇ 4 within the fourth frame are turned on with the dots ⁇ 3 within the remaining frame turned off and at the second timing for the dots ⁇ , the dots ⁇ 2 within the second frame, the dots ⁇ 3 within the third frame and the dots ⁇ 4 within the fourth frame are turned on with the dots ⁇ 1 within the remaining frame turned off.
- FIGS. 5A and 5E illustrate perfect turn-off display and perfect turn-on display, respectively.
- a prior art employing the dot base thin-out method described as above does not take the aforementioned dither technique and conventionally, when the dither method and the dot base thin-out method are used in combination, there arises a problem that the display flow is increased and the picture quality degradation is aggravated.
- the present invention contemplates elimination of the above conventional drawbacks and has for its object to provide a liquid crystal display apparatus and method capable of suppressing the display flow and preventing the picture quality degradation from occurring even when displaying data pursuant to the dither method.
- a decision is made as to whether color display information is to take a display form pursuant to the dither method, and when the decision results are positive and indicate that the color display information takes the display form pursuant to the dither method, the color display information is converted into liquid crystal luminance display information in accordance with a frame unit thin-out method corresponding to the color display information when the decision results are negative, the color display information is converted into liquid crystal luminance display information in accordance with a dot base thin-out method.
- the present invention having the above construction can ensure exellent liquid crystal display without inviting the picture quality degradation.
- FIG. 1 is a block diagram showing the essential part of an embodiment of the invention
- FIGS. 2A to 2E are diagrams useful to explain thin-out operation in unit of frame
- FIGS. 3A to 3F are diagrams useful to explain the principle of dither decision together with an example of decision results
- FIG. 4 is a diagram useful to explain a fundamental dot set in the dot base thin-out method.
- FIGS. 5A to 5E are diagrams useful to explain dot base thin-out operation at a period of 4 frames.
- the present inventors have confirmed that in display based on the dot base frame thin-out method, display flow (which gives a visual feeling that the image runs in the right or left direction) is slightly generated in a display in all-over painting fashion of uniform luminance (at a uniform thin-out rate) but therein, such a flicker as generated in the frame base thin-out method by which thin-out operation is effected at the same timing over the entire screen is not found and the display can be stable.
- adjacent two dot sets on the screen are thinned out at different thin-out rates.
- the number of expressible kinds of color can be increased.
- a thin-out rate can be realized which corresponds to pink visually.
- the present inventors have found that when display data of a display form pursuant to the the dither method undergoes the dot base frame thin-out operation, the aforementioned display flow is aggravated and the picture display becomes unstable, thus aggravating the picture quality degradation.
- reference numeral 1 designates serial input display data to be subjected to gradation display
- 2 a serial/parallel converter adapted to convert the input serial display data into 4-bit parallel data and deliver the parallel data as designated at 5, 4 a latch circuit
- 10 a dot base thin-out data generator for generating data 11 pursuant to the aforementioned dot base thin-out method
- 8 a frame base thin-out data generator for generating frame base thin-out data 9.
- the frame unit thin-out data generator 8 and dot base thin-out data generator 10 are responsive to a head line clock signal and a line clock signal (see FIG.
- each of the generators generates 8 kinds of thin-out data.
- Reference numeral 6 designates a dither decider for deciding whether the 4-bit parallel data 5 is dither display data and generating, in accordance with the decision results, a select signal 7 which controls a thin-out data selector 12.
- the selector 12 is responsive to the select signal 7 to select the thin-out data so that either one of the frame unit thin-out data 9 and dot base thin-out data 11 is selected and delivered as selected thin-out data 13.
- a data decoder 14 responds to the 4-bit parallel data 5 to decode the selected thin-out data 13 and decoded data is delivered as 4-bit gradation display data 16 through a latch 15. More particularly, the data decoder 14 selects one kind of data from, for example, 8 kinds of selected thin-out data in accordance with the 4-bit parallel data. In other words, one kind of thin-out data is selected from various kinds of thin-out data generated from the data generators 8 and 10 under the direction of the color display information and delivered to the liquid crystal panel.
- the latches 4 and 15 operate in synchronism with a latch clock signal 3.
- the X driver for driving the liquid crystal panel in X-axis direction typically fetches display data for determination of turn-on/off of display 4 bits by 4 bits or 8 bits by 8 bits simultaneously. Therefore, by performing decision as to whether the display form is pursuant to the dither method, that is, dither decision in unit of 4 bits, the decision results can be applied to either one of the 4-bit type and 8-bit type X drivers and the display mode can be switched to one commensurate with the X driver in use.
- liquid crystal Since the liquid crystal is activated to provide a display of luminance proportional to the effective value of applied voltage, displays of identical luminance can be obtained in different thin-out modes as far as the effective values of applied voltage are identical in these modes and therefore no problem is encountered in display luminance.
- the dot base thin-out data generator 10 and frame base thin-out data generator 8 shown in FIG. 1 will now be described.
- FIG. 4 shows the fundamental dot set in the dot base and FIGS. 5A to 5E show thin-out operation effected at a period of four frames.
- the fundamental dot set 18 is constructed of 4 dots of which two are in X-axis direction and two are in Y-axis direction on the liquid display panel 17 and provides dot base thin-out data.
- the dot base thin-out data generator 10 generates display data 11 for each frame of the fundamental dot set 18 at two different timings, one for the dots ⁇ and the other for the dots ⁇ , as shown in FIGS. 5A to 5E.
- the frame base thin-out data generator 8 generates display data 9 for each frame by thinning out all dots of the fundamental dot set 18 at the same timing as shown in FIGS. 2A to 2E.
- dot base thin-out data and frame base thin-out data will now be described with reference to FIGS. 5A to 5E and FIGS. 2A to 2E, respectively.
- hatched dots indicate turned-on dots.
- an X-directionally odd and Y-directionally odd dot and an X-directionally even and Y-directionally even dot are turned on at the timing for the dots ⁇ and an X-directionally even and Y-directionally odd dot and an X-directionally odd and Y-directionally even dot are turned off at the timing for the dots ⁇ , within the second frame all the dots are turned off, within the third frame the state within the first frame is inverted, and within the fourth frame all the dots are turned off as within the second frame.
- each one dot of the fundamental dot set 18 it is turned on once and turned off three times throughout the four frames. In other words, 1/4 turn-on is achieved in a display in unit of four frames.
- all dots of the fundamental dot set 18 are thinned out at the same timing so that within the first frame, all the dots are turned on and within the second to fourth frames, all the dots are turned off, indicating that in conneciton with each one dot of the fundamental dot set, it is turned on once throughout the four frames.
- evaluation of display quality of the all-over painting like display obtained in accordance with the two kinds of thin-out method and display quality of the dither display indicates that gradation display of higher quality can be realized by using the frame base thin-out method in combination with data of dither display form and the dot base thin-out method in combination with data of another display form.
- the dither decider 6 decides whether the 4-bit parallel data 5 is of dither display form and produces the decision results, an example of which is shown in FIGS. 3A to 3F.
- A, B and C represent different pieces of data and the dither display form is settled when the following conditions are satisfied:
- display data of 4 dots satisfying the conditions (1) and (2) for the dither display is determined to be of dither display form by means of the dither decider 6 and a select signal 7 for the data selector 12 is produced from the decider 6.
- a select signal 7 for the data selector 12 is produced from the decider 6.
- either frame base thin-out data 9 or dot base thin-out data 11 is selected and delivered as selected thin-out data 13.
- the selected thin-out data 13 is decoded under the direction of the 4-bit parallel data to provide gradation display data 16 which is delivered through the latch 15.
- gradation display can be carried out in accordance with unit frame thin-out data, and for data of another display form, gradation display can be carried out in accordance with dot base thin-out data.
- Display data 1 received serially is converted into 4-bit parallel data 5.
- the 4-bit parallel data is determined to be of a dither display form or not by means of the dither decider 6 and decision results are sent to the data selector 12.
- the data selector 12 selects either frame unit thin-out data or dot base thin-out data in accordance with the decision results and the data decoder 14 decodes the selected data under the direction of the 4-bit parallel data 5 to produce gradation display data 16 which is delivered to the liquid crystal panel.
- the dither decision is carried out in unit of 4-bit parallel data and that the dither decider 6 can be constructed of a simple decoder.
- the display data has been described as being limited to a dither display form. More generally, however, decision may be made on a display pattern which would have a trouble with display quality when displayed, such a display pattern being termed A pattern herein. Then, when the A pattern is to be displayed, the pattern display is carried out in accordance with a display method (C method) which does not degrade the display quality but when the display pattern is determined not to be of the A pattern (or determined to be of B pattern), the pattern display is carried out in accordance with a D display method different from the C method.
- C method display method
- a specified display method is used for a specified display pattern to prevent degradation of the display quality and ensure stable display.
- the number of the kinds of specified display pattern is not limited to one. Assuming that N kinds of specified display pattern are available, display methods dedicated to the respective kinds may be employed.
- gradation display is carried out in accordance with a specified A pattern such as a dither display form
- gradation display is carried out in accordance with a specified C method such as the frame unit thin-out method
- a D method such as the dot base thin-out method different from the C method
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Liquid Crystal Display Device Control (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
- Liquid Crystal (AREA)
Abstract
Description
Claims (8)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1-146651 | 1989-06-12 | ||
JP01146651A JP3106466B2 (en) | 1989-06-12 | 1989-06-12 | Liquid crystal display device and method |
Publications (1)
Publication Number | Publication Date |
---|---|
US5220314A true US5220314A (en) | 1993-06-15 |
Family
ID=15412551
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US07/532,811 Expired - Lifetime US5220314A (en) | 1989-06-12 | 1990-06-04 | Liquid crystal display apparatus and method of performing liquid crystal display |
Country Status (5)
Country | Link |
---|---|
US (1) | US5220314A (en) |
EP (1) | EP0402848B1 (en) |
JP (1) | JP3106466B2 (en) |
KR (1) | KR930005377B1 (en) |
DE (1) | DE69033323T2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5638088A (en) * | 1992-06-18 | 1997-06-10 | Hitachi, Ltd. | Method of driving STN liquid crystal panel and apparatus therefor |
US5648796A (en) * | 1993-05-05 | 1997-07-15 | U.S. Philips Corporation | Method and device for generating grey levels in a passive martix liquid crystal display screen |
US5774104A (en) * | 1990-09-11 | 1998-06-30 | Northern Telecom Limited | Co-ordinate addressing of liquid crystal cells |
US20040207592A1 (en) * | 2003-04-21 | 2004-10-21 | Ludden Christopher A. | Display system with frame buffer and power saving sequence |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4812151B2 (en) * | 2000-02-25 | 2011-11-09 | 京セラ株式会社 | Liquid crystal gradation display circuit and liquid crystal display device |
KR100997978B1 (en) * | 2004-02-25 | 2010-12-02 | 삼성전자주식회사 | Liquid crystal display |
CN111554245B (en) * | 2020-05-22 | 2021-10-08 | Tcl华星光电技术有限公司 | Display device driving method and display device |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4823120A (en) * | 1986-09-12 | 1989-04-18 | Apple Computer, Inc. | Enhanced video graphics controller |
US4956638A (en) * | 1988-09-16 | 1990-09-11 | International Business Machines Corporation | Display using ordered dither |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63181589A (en) * | 1987-01-23 | 1988-07-26 | Hitachi Ltd | Video signal converting circuit |
JP2749035B2 (en) * | 1987-05-20 | 1998-05-13 | 株式会社日立製作所 | Liquid crystal display |
FR2621728B1 (en) * | 1987-10-09 | 1990-01-05 | Thomson Csf | SYSTEM FOR VIEWING HALF-TONE IMAGES ON A MATRIX SCREEN |
-
1989
- 1989-06-12 JP JP01146651A patent/JP3106466B2/en not_active Expired - Lifetime
-
1990
- 1990-06-04 US US07/532,811 patent/US5220314A/en not_active Expired - Lifetime
- 1990-06-07 KR KR1019900008317A patent/KR930005377B1/en not_active IP Right Cessation
- 1990-06-12 DE DE69033323T patent/DE69033323T2/en not_active Expired - Lifetime
- 1990-06-12 EP EP90111076A patent/EP0402848B1/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4823120A (en) * | 1986-09-12 | 1989-04-18 | Apple Computer, Inc. | Enhanced video graphics controller |
US4956638A (en) * | 1988-09-16 | 1990-09-11 | International Business Machines Corporation | Display using ordered dither |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5774104A (en) * | 1990-09-11 | 1998-06-30 | Northern Telecom Limited | Co-ordinate addressing of liquid crystal cells |
US5638088A (en) * | 1992-06-18 | 1997-06-10 | Hitachi, Ltd. | Method of driving STN liquid crystal panel and apparatus therefor |
US5977943A (en) * | 1992-06-18 | 1999-11-02 | Hitachi, Ltd. | Method of driving STN liquid crystal panel and apparatus therefor |
US6559823B1 (en) | 1992-06-18 | 2003-05-06 | Hitachi, Ltd. | Method of driving STN liquid crystal panel and apparatus therefor |
US5648796A (en) * | 1993-05-05 | 1997-07-15 | U.S. Philips Corporation | Method and device for generating grey levels in a passive martix liquid crystal display screen |
US20040207592A1 (en) * | 2003-04-21 | 2004-10-21 | Ludden Christopher A. | Display system with frame buffer and power saving sequence |
US7102610B2 (en) * | 2003-04-21 | 2006-09-05 | National Semiconductor Corporation | Display system with frame buffer and power saving sequence |
US20070018928A1 (en) * | 2003-04-21 | 2007-01-25 | National Semiconductor Corporation | Display system with frame buffer and power saving sequence |
US8416173B2 (en) | 2003-04-21 | 2013-04-09 | National Semiconductor Corporation | Display system with frame buffer and power saving sequence |
Also Published As
Publication number | Publication date |
---|---|
JPH0312692A (en) | 1991-01-21 |
EP0402848A3 (en) | 1991-10-16 |
KR930005377B1 (en) | 1993-06-19 |
JP3106466B2 (en) | 2000-11-06 |
DE69033323T2 (en) | 2000-07-27 |
EP0402848A2 (en) | 1990-12-19 |
KR910001628A (en) | 1991-01-31 |
EP0402848B1 (en) | 1999-10-13 |
DE69033323D1 (en) | 1999-11-18 |
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